// ================================================================
// Copyright (C) 2007 Google Inc.
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//      http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ================================================================
//
//  NSImage+IconData.m
//  MacFUSE
//
//  Created by ted on 12/28/07.
//
#import <AppKit/AppKit.h>
#import <CoreServices/CoreServices.h>
#import <Accelerate/Accelerate.h>
#import "NSImage+IconData.h"

@implementation NSImage (IconData)

- (NSData *)icnsDataWithWidth:(int)width {
  SInt32 version;
  Gestalt(gestaltSystemVersionMinor, &version);

  OSType icnsType;
  switch (width) {
    case 128:
      icnsType = 'ic07';  // kIconServices128PixelDataARGB
      break;
    case 256:
      icnsType = kIconServices256PixelDataARGB;
      break;
    case 512:
      icnsType = 'ic09';  // kIconServices512PixelDataARGB
      break;
      
    default:
      NSLog(@"Invalid icon width: %d", width);
      return nil;      
  }
  
  // TODO: We should probably set the image source rect to preserve the aspect
  // ratio of the original image by clipping part of it.  This leads to a
  // smaller .icns file result, which is nice. Basically clip the top and 
  // bottom (or left and right) of part of the source image. This might also
  // lead to better performance?

  // See Cocoa Drawing Guide > Images > Creating a Bitmap
  // Also see IconStorage.h in OSServices.Framework in CoreServices umbrella.
  NSRect rect = NSMakeRect(0, 0, width, width);
  size_t bitmapSize = 4 * rect.size.width * rect.size.height;
  Handle bitmapHandle = NewHandle(bitmapSize);
  unsigned char* bitmapData = (unsigned char *)*bitmapHandle;
  NSBitmapFormat format = NSAlphaFirstBitmapFormat;

  // TODO: The docs say that the image data should be in non-premultiplied
  // format, but when NSAlphaNonpremultipliedBitmapFormat is used on 10.5 we get 
  // an error about invalid parameters for graphics context. We should try this
  // again in future 10.5 releases in case it gets fixed. Until then, maybe 
  // we should use vImageUnpremultiplyData_ARGB8888(...) on 10.5?
  if (version != 5) {
    format |= NSAlphaNonpremultipliedBitmapFormat;
  }
  NSBitmapImageRep* rep = 
    [[[NSBitmapImageRep alloc] 
      initWithBitmapDataPlanes:&bitmapData  // Single plane; just our bitmapData
                    pixelsWide:rect.size.width
                    pixelsHigh:rect.size.height
                 bitsPerSample:8 
               samplesPerPixel:4  // ARGB
                      hasAlpha:YES 
                      isPlanar:NO 
                colorSpaceName:NSCalibratedRGBColorSpace 
                  bitmapFormat:format
                   bytesPerRow:0  // Let it compute bytesPerRow and bitsPerPixel
                  bitsPerPixel:0] autorelease];
  [NSGraphicsContext saveGraphicsState];
  NSGraphicsContext* context = 
    [NSGraphicsContext graphicsContextWithBitmapImageRep:rep];
  [NSGraphicsContext setCurrentContext:context];
  NSImageInterpolation interpolation = [context imageInterpolation];
  [context setImageInterpolation:NSImageInterpolationHigh];
  [self drawInRect:rect fromRect:NSZeroRect operation:NSCompositeCopy fraction:1.0];
  [context setImageInterpolation:interpolation];
  [NSGraphicsContext restoreGraphicsState];

  // On Tiger, the above actually returns RGBA data. Probably a bug in Tiger?
  // We use vImage to permute from RGBA -> ARGB in place on the data buffer.
  if (version == 4) {
    vImage_Buffer src;
    src.data = bitmapData;
    src.height = rect.size.height;
    src.width = rect.size.width;
    src.rowBytes = [rep bytesPerRow];
    vImage_Buffer dst = src;  // We'll just overwrite our bitmap data.
    uint8_t permuteMap[] = { 3, 0, 1, 2 };  // Used to go from RGBA -> ARGB
    vImagePermuteChannels_ARGB8888(&src, &dst, permuteMap, kvImageDoNotTile);
  }
  
  // We need to use SetIconFamilyData here rather than just setting the raw
  // bytes because icon family will compress the bitmap for us using RLE. This
  // is described in http://ezix.org/project/wiki/MacOSXIcons
  Handle familyHandle = NewHandle(0);
  SetIconFamilyData((IconFamilyHandle)familyHandle, icnsType, bitmapHandle);
  DisposeHandle(bitmapHandle);
  NSData* data = 
    [NSData dataWithBytes:*familyHandle length:GetHandleSize(familyHandle)];
  DisposeHandle(familyHandle);
  return data;
}

@end